Understanding The Linux Kernel Initcall Mechanism Creating Dynamic Function-Pointer Call Tables卷染机
Trevor Woerner
Understanding The Linux Kernel Initcall Mechanism:Creating Dynamic Function-Pointer Call Tables
溴代环丙烷Copyright©2003,2006Trevor Woerner
Copyright(c)2003,2006Trevor Woerner
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Revision History
Revision0.126August2003Revised by:tlw
Document start.
Revision1.023September2003Revised by:tlw
Document completed and released.
Revision1.111October2006Revised by:tlw
Updated to latestiesp-144
Table of Contents
Abstract (i)
1.Introduction (1)
Date and Version (1)
Notation (1)
Architecture (1)
Tools (1)
"objdump-t"output format (1)
2.Motivation (7)
3.Background Information (9)
Executable File Formats (9)
Linker (10)
Compiler (10)
4.Simple Examples (11)
光触媒滤网
Before/After main() (11)
Section and Object Layout (11)
Putting Objects into their own ELF Sections (19)
5.How the Linux Kernel initcall Mechanism Works (25)
6.From the Kernel To Stand-Alone Code (29)
7.References (31)
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Abstract
While browsing through the Linux kernel,I came upon a technique for creating a
segment of function pointers which can be called at a later time in the order that they
are inserted into the segment.The kernel uses this mechanism to call device driver
initialization routines at boot-up.
I had a hard timefinding clear information about what was going on and how it
worked.After much googling(and some code doodling)I understand what is hap-
pening.This paper is an attempt at putting what I understand of this process down
on paper so others may hopefullyfind it useful.
Note:This technique depends on,and requires the use of,the GNU compiler and
linker tools.Additionally,the ELF binary executable format must be used.This is
not a general-puropse ANSI-C compliant technique.
Please direct any useful observations or comments to(remove spaces and adjust the
formatting):twoerner.k AT gmail DOT com
i
Abstract ii
